The present invention relates to image processing systems and methods and more particularly to image editors that employ color key editing.
Various kinds of image processing systems may employ color key editing or selection in image editing operations.
Color key selection uses pixel values to determine which pixels are to be modified in accordance with an editing operation. Editing or colorizing is then performed on all of the selected pixels (typically, defined by a bit mask) in accordance with a conventional editing operation such as TV Image or Line Art. The selected pixels are chosen by some suitable means.
Color key editing is often defined as a procedure in which pixel selection and colorizing are combined in a pixel-by-pixel operation.
One type of image processing system is a duplicator system in which a stored electronic image can be edited and applied to a platen to produce a hard copy output. Another system is a reprographic system in which a digital image is scanned from a hard copy input and then processed through an image editor to generate an edited hard copy output from a laser printer or the like. In an image edit system, an image editor processes stored images in accordance with edit operations and stores the edited images electronically for use in other systems.
Color editing generally is a process in which some means is provided for defining image pixels to which color changes are to be applied. In the prior art, for example, full color images are interactively edited on color display monitors of limited bit-depth using the techniques disclosed in the above referenced patent application Ser. No. 07/517,895.
However, color editing typically has been limited to adjusting all of the color lookup table entries that correspond to pixels in a well-defined closed region of an encoded form of the ETT full color image. Editing productivity and editing quality have accordingly been adversely affected. Thus, it may be difficult to define a region having only the colors that are to be changed, and as a result some colors may not be changed that should be changed or vice versa.
For example, consider an image of a tree with sky showing through the leaves. The sky color may be greenish because of erroneous use of tungsten indoor film for outdoor picture taking. As a result, tiny bits of sky showing through small spaces between the leaves are off-color. Correcting the sky color of the small tree spaces without washing out the spaces is at best very difficult with known prior art procedures.
In any case, the known prior art has had no capability for adaptive editing where editing operation on a pixel depends on the pixel color.
The following prior patents have been identified as having limited relevance to the present invention:
1. U.S. Pat. No. 4,167,729, "Apparatus For Obtaining Multi-Spectral Signatures", dated Sep. 11, 1979, filed by Dempster S. Christenson, et al.
2. U.S. Pat. No. 4,488,245, "Method And Means For Color Detection And Modification", dated Dec. 11, 1984, filed by George W. Dalke, et al.
3. U.S. Pat. No. 4,649,423, "Method and Circuit Arrangement For Selective Correction Of Hues And Colors", dated Mar. 10, 1987, filed by Ingo Hoffrichter, et al.
4. U.S. Pat. No. 4,727,425, "Pixel Color Modification Using Look-Up Tables In Image Reproduction System", dated Feb. 23, 1988, filed by Clive L. Mayne, et al.
5. U.S. Pat. No. 4,731,662, "Image Processing Method For Processing An Image Signal Differently Depending On The Range Of An Image Characteristic Thereof Relative To The Range Within Which Output Device Can Reproduce The Image Characteristic", dated Mar. 15, 1988, filed by Yoshiro Udagawa et al.
6. U.S. Pat. No. 4,758,885, "Method of Processing Color Image", filed Jul. 19, 1988, filed Takashi Sasaki, et al.
7. U.S. Pat. No. 4,989,080, "Color Correction Device With A Hue Area Judgment Unit To Determine Correction Parameters", filed Jan. 29, 1991, filed by Takanori Ito.
8. U.S. Pat. No. 4,992,861, "Color Image Reproduction Apparatus Having A Digitally Operated Look-Up Table Constructed by Means of a Least Squares Algorithm", dated Feb. 12, 1991, filed by John R. D'Errico.
9. U.S. Pat. No. 4,992,864, "Image Processor Having Density Indicator", dated Feb. 12, 1991, filed by Kazuya Akiyama.
10. U.S. Pat. No. 5,012,333, "Interactive Dynamic Range Adjustment System For Printing Digital Images", dated Apr. 30, 1991, filed by Hsien-Che Lee, et al.